The invention relates to a pump having the features comprising a stator having a base plate and two clamping plates between which the base plate is clamped. A diaphragm spans the annular surface of the base plate having an inlet and an outlet. The diaphragm is pushed sequentially onto the annular surface by sequentiallly activated push rods in order to move the fluid to be pumped from the inlet to the outlet. Such a pump is known from DE-295 11 966 U. The known pump has a stationary arrangement comprised of a base plate and two clamping plates between which the base plate is clamped. An annular surface is provided at the surface of the base plate which extends over a part-circular portion or a full circle and is covered by a diaphragm clamped at its edges by a clamping plate tightly to the base plate. Between the diaphragm and the annular surface of the base plate a pump channel is provided into which an inlet and an outlet, extending through the base plate, open. The pump channel connects the inlet and the outlet along the longer path while the shorter path between the inlet and the outlet is blocked. A rotor is positioned above the diaphragm and is coaxially arranged to the annular surface. It comprises a plurality of rollers which act on the diaphragm by axially moveable pressure transmitting members arranged on a circle above the diaphragm in order to press it locally against the annular surface so that the diaphragm interrupts the path from the inlet to the outlet at circumferentially proceeding locations in order to thus provide the desired pumping action. The stroke of the pressure transmitting members can be adjusted by a control ring which is arranged above one of the clamping plates in the vicinity of the rollers. This also serves to adjust the pumping output of the pump.
The clamping plate, which is arranged at the face of the diaphragm facing away from the base plate, is annularly embodied and secured by screwing with a plurality of screws arranged about its circumference to the oppositely arranged clamping plate so that at the same time the edge of the diaphragm is fixedly clamped. A threaded rod extends coaxially to the rotor shaft through a circular opening of the annular clamping plate to the exterior. A control nut is threaded onto the rod and allows to adjust by a spring force the pressure with which the rollers act on the diaphragm. By turning the control nut, the conveying pressure of the pump can be adjusted.
The diaphragm and the base plate which delimit together the pumping channel, are wear parts and must be exchanged from time to time, especially for abrasive media such as mortar. In the known pump the screws which screw the clamping plates together as well as the control nut must be removed for this purpose. Subsequently, the base plate and the diaphragm can be removed and exchanged if needed.
The present invention has the object to simplify manipulation and servicing of the pump.